Practice question

Question

In standard or batch cultures, cells are grown in a fixed volume of medium. As they grow, nutrients are consumed and metabolites accumulate. Eventually, cultures may stop growing because of nutrient depletion and accumulation of toxic products. The following procedures may prolong the life of batch cultures: A. Gradual addition of fresh medium and increasing volume of the cultureB. Replacing a constant fraction with an equal volume of fresh mediumC. Occasional removal of used medium and reducing growth factors in the mediumD. Intermittently adding serum and growth factors to the medium Which one of the following combinations will ensure healthy growth of cells in culture?